Supplementary Tables E1-E3. Propensity score matching versus coarsened exact matching in observational comparative effectiveness research

Supplementary materials – tables:Table E1a. Characteristics of PSM strategies for comparison oneTable E1b. Characteristics of PSM strategies for comparison twoTable E2a. Coarsening of covariates used in CEM for comparison oneTable E2b. Coarsening of covariates used in CEM for comparison twoTable E3a. Characteristics of CEM strategies for comparison oneTable E3b. Characteristics of CEM strategies for comparison twoSupplementary materials – figuresFigure E1a. Selection process for comparison oneFigure E1b. Selection process for comparison twoFigure E2a. Distribution of baseline covariates by PSM caliper width for comparison oneFigure E2b. Distribution of baseline covariates by PSM caliper width for comparison twoFigure E3a. Distribution of baseline covariates by CEM strategy for comparison oneFigure E3b. Distribution of baseline covariates by CEM strategy for comparison twoSupplementary materials – tablesTable E1a. Characteristics of PSM strategies for comparison oneTable E1b. Characteristics of PSM strategies for comparison twoTable E2a. Coarsening of covariates used in CEM for comparison oneTable E2b. Coarsening of covariates used in CEM for comparison twoTable E3a. Characteristics of CEM strategies for comparison oneTable E3b. Characteristics of CEM strategies for comparison twoAbstractAims & Methods: We compared propensity score matching (PSM) and coarsened exact matching (CEM) in balancing baseline characteristics between treatment groups using observational data obtained from a pan-Canadian prostate cancer radiotherapy database. Changes in effect estimates were evaluated as a function of improvements in balance, using results from RCTs to guide interpretation. Results: CEM and PSM improved balance between groups in both comparisons, while retaining the majority of original data. Improvements in balance were associated with effect estimates closer to those obtained in RCTs. Conclusions: CEM and PSM led to substantial improvements in balance between comparison groups, while retaining a considerable proportion of original data. This could lead to improved accuracy in effect estimates obtained using observational data in a variety of clinical situations.